2,6-Bis-(diethanolamino)-4,8-dipiperidino-pyrimido-[5,4-d]-pyrimidine (generic name: Dipyridamole) has for a long time been used as a coronary dilator; it was first described in British Pat. No. 807,826. Likewise, 1,2-diphenyl-3,5-dioxo-4-(2-phenylsulfinyl-ethyl)-pyrazolidine (generic name: Sulfinpyrazone) has for a long time been used as an anti-gout agent; it was first described in Helv. chim. Acta. 44, 236 (1961). Both therapeutics were subsequently also found to have a good antithrombotic effect; see, for example, Therapiewoche 26, 8464-8489 (1976).
In the case of both substances, however, a relatively high dosage is required for of an antithrombotic effect, where certain side-effects of both compounds become noticeable; with diphyridamole the side effects are certain circulatory effects which show themselves as headaches; with sulfinpyrazone they are stomach pains due to the ulcerogenic effect of this substance at high dosages.